Solution:
Without knowing what the capacity did, I can’t actually help you there, however to clear the blunder, put the capacity in your functions.php record like so (as you’ve done)…
function custom_modify_title($args=array())
{
return $args;
}
After that, you may be able to start restoring some of that functionality you lost by diving in here: http://manos.malihu.gr/page-scroll-to-id-for-wordpress/